Apertured sleeve-shaped members for use in carrying out roof-bolting by means of bolts fastened in bore holes

ABSTRACT

The present invention relates to an apertured sleeve-shaped member made from a relatively rigid but resilient material and provided with a longitudinal slit which permits the diameter of the member to be varied by compression. The sleeve-shaped mamber is adapted to be filled with cement mortar and used in roofbolting for insertion into bore holes of different diameter.

United States Patent 11 1 Lundkvist Aug. 26, 1975 1 APERTURED SLEEVE-SHAPED MEMBERS 1.673.729 6/1928 Barnes 52/170 FOR USE IN CARRYING OUT 2,241,343 5/1941 61/45 B UX 2.682152 6/l954 Bicrcr 1 61/45 B R091? BOLTING BY MEANS OF BOLTS 2,849,866 9 1958 Flygarc ct a1. 61/45 B FASFENED 1N BORE HOLES 2.905.282 9/1959 Miller 52/108 [76] lnventor: Alfred Ingevald Lundkvist, 31391731 7/1964 Liddcn 1 61/54 Krokusvagen 12, 29150 3,699,687 10/1972 Bourland 61/45 B Kristianstad, Sweden Primary ExaminerDennis L. Ta lor [22] Filed. Mar. 4, 1974 Attorney, Agent, or FirmYoung & Thompson [2]] App]. No: 448,043

[] Foreign Application Priority Data 1 1 ABSTRACT Swcdcn 7303376 The present invention relates to an apertured sleeveshaped member made from a relatively rigid but resilg? g g i g ient material and provided with a longitudinal slit 15 which permits the diameter of the member to be var- 1 0 108 ied by compression. The sleeve-shaped mamber is adapted to be filled with cement mortar and used in References Cited gosrilglting for insertion Into bore holes of d1fferent UNITED STATES PATENTS 982,380 H1911 Martin 52/170 3 Claims, 4 Drawing Figures APERTURED SLEEVE-SHAPED MEMBERS FDR USE IN CARRYING OUT ROQF-BOLTING BY MEANS OF BOLTS F ASTENED IN BORE HOLES The present invention relates to improved means for carrying out roof-bolting in a mine, shaft or similar cavity in the rock and, more particularly, provides an improved apertured sleeve-shaped member for use in carrying out such roof-bolting by means of bolts fastened in bore holes in the rock.

The general method of roof bolting by means of bolts fastened in bore holes has been practised for a long time past, inter alia in accordance with the disclosure of the US. Pat. No. 2,849,866. This prior method fundamentally comprises inserting an apertured tubular member of smaller diameter than the bore hole diame ter and containing cement mortar or similar material into said bore hole and thereupon introducing the bolt which has a smaller diameter than the said tubular member into the latter forcing the mortar out through the apertures thereof, so that the mortar besides filling the annular space between the bolt and the tube will also fill the annular space between the tube and the bore hole wall and after setting will form a hard body rigidly connecting the bolt with the rock substantially along the whole of its length.

In practice the apertured tube or sleeve has also been made in the form of two mating halves which after being filled with cement mortar and assembled must be tied together by means of wire to form a unit.

However, the usefulness of the method is limited in an embarrassing way by the fact that almost every bore hole diameter requires a particular corresponding tube diameter, so that a number of different tube diameters has to be kept in stock.

The principal object of the present invention is to provide an apertured sleeve-shaped member by which the above-mentioned drawback is avoided.

Another object of the invention is to provide an apertured sleeve-shaped member as defined by which the handling thereof on the site of application is simplified.

Still another object of the invention is to provide a tubular or sleeve-shaped member of the kind stated as an integral unit of appropriate rigidity although made from thinner sheet material or more resilient material than prior tubular members for similar applications.

According to the invention, the said and further objects are achieved by the provision of an apertured sleeve-shaped member which is made from a relatively rigid but resilient material, and the circumferential surface of which is interrupted by a longitudinal relatively broad slit through which the cement mortar can be introduced into the sleeve-shaped member and which on exercising a radial pressure on the member on both sides of the said slit permits a variation of the diameter of the member while maintaining a desired substantially circular cross-section as well as an adaptation thereof to bore holes of different sizes, possibly by causing the slit edges to overlap, the set diameter being fixable by means of fixing members, e.g. in the form of thin rings, capable of being mounted on the sleeveshaped member.

The width of the slit has to be of such size that the sleeve-shaped member can be filled with mortar composition without difficulty. Before comprising the sleeve-shaped member said width preferably amounts to at least about one forth of the sleeve circumference.

After charging the member with mortar and compressing it to the desired dimension, this dimension may be fixed, for example, by threading thin sheet metal of plastic rings onto the sleeve member. Clearly, the fixing may also take place otherwise for example by tieing with wire or by hooking on suitably designed clamps provided with hooks, or the like.

For illustrating the invention reference is had to an embodiment thereof represented in the accompanying drawing, in which:

FIG. 1 is perspective view of a sleeve-shaped member constructed according to the invention;

FIGS. 2 and 3 are end views of the sleeve member after compressing it to different smaller diameters;

FIG. 4 is a longitudinal sectional view through a bore in the roof of an excavation, showing the inventions in use.

Referring to FIG. 1, the sleeve-shaped member 1 which may have a length of several meters consists of a relatively stiff but resilient material and is provided, in a manner known per se, with apertures 2 substantially along the whole of its length. The material may be a metal, such as sheet steel, or a suitable plastic. Extending along the whole length of the sleeve is a slit 3 through which a mortar composition may be introduced into the sleeve. This slit should have such a width that charging with the cement mortar can take place conveniently, and as a rule a slit width corresponding to about one forth of the sleeve circumference will be suitable. The thickness of the material has to be selected so that the sleeve will be self-supporting and will not bend at the same time as the thickness is not allowed to be larger than to enable the sleeve to be pressed together while utilizing the resilient compliance thereof. Sheet steel has a thickness of 0.30.7 mm, for example 0.5 mm, has been tried successfully. The thickness is of course also dependent on the length of the member.

Through the compressiblity it becomes possible to adapt the sleeve diameter to the bore hole diameter, i.e. one and the same type of sleeve may be used for bore holes of different sizes. The sleeve may be filled with mortar composition and can be used without first being compressed if it is intended to be used in a bore hole of a corresponding diameter. In tests carried out it has been found that after filling with mortar composition and fixing its diameter the sleeve member will retain the mortar composition in a horizontal as well as a vertical position also with the slit 3 open. Altematively, as shown in FIG. 2, the sleeve may be compressed, for example so that the slit edges 4, 4 meet, or finally, as is seen in FIG. 3, so that one slit edge overlaps the other. A considerable range of diameters may thus be covered by a suitable choice of ductile and resilient material for the sleeve.

After compressing the sleeve with its content of mm tar composition to the desired diameter, this is fixed, for example, by threading a number of thin rings 5 or metal or plastic onto the sleeve and spacing them in a suitable way.

The advantages of the new improved sleeve member may be briefly summarized as follows:

1. A sleeve member of a given size may be used for bore holes having diameter within a relatively large range. The assortment of the supplier is thereby reduced. and the stock in hand of the supplier and on the site of application is simplified and made cheaper.

2. The design of the sleeve simplifies the handling thereof on the site of application in filling it with mortar composition and converting it into a complete pack or unit for introduction into the bore hole. This result is obtained by the fact that the sleeve member is filled directly as a unit and assemblage of sleeve halves or sleeve parts is avoided as well as by the fact that a timewasting tieing with wire advantageously can be replaced by quickly mountable fixing rings.

3. The sleeve member in the form of a single integral unit provides increased stiffness in relation to prior structures with separate mating parts. The increased stiffness permits the utilization of thinner sheet metal or materials of a more ductile kind, for example plastics of any suitable class, without any weakened final product, i.e. an apertured sleeve ready for use, resulting therefrom. This circumstance may result in lower material and production costs and lower freight charges.

4. In the case of a bore hole which consists of an outer larger part made by means of a larger drill, and a smaller part made by a smaller drill, the need of two sleeve-shaped members which would have to be introduced one after the other may be avoided by squeezing a single sleeve-shaped member according to the invention to different extents at the outer end and at the inner end and fixing the diameters desired by threading on suitable fixing-rings or the like, so that the sleeve Shaped member will be slightly tapering. Thereby the work is simplified. FIG. 4 shows the invention in use, in the same Way as in the above-identified patent. The borehole 6 in the roof of an excavation receives the member 1 encircled by rings and filled with cement mortar 7, after which the roof bolt 8 is inserted which drives mortar 7 through apertures 2 to fill the space between member 1 and the side walls of bore-hole 6 where it hardens.

What l claim is:

1. In a roof bolt emplaced in a bore-hole, comprising a sleeve-shaped member disposed in the bore-hole and having a plurality of apertures therethrough, a bolt extending lengthwise the interior of said sleeve-shaped member, and a quantity of cement mortar surrounding the bolt and extending through said apertures and filling the space between said sleeve-shaped member and the side walls of the bore-hole; the improvement in which the sleeve-shaped .member consists of a relatively rigid by resilient material, the circumferential surface of said member being interrupted by a longitudinal and relatively wide slit which allows the introduction of the cement mortar into the interior of said member and which under the influence of a radial pressure on said member on both sides of the said slit allows a variation of the diameter of the member while maintaining a desired, substantially circular cross-section and an adaptation thereof to bore holes of different sizes, and fixing means surrounding the sleeve-shaped member and maintaining said member compressed to a smaller diameter than when said member is uncompressed.

2. Structure as claimed in claim 1, wherein said member is compressible to such an extent that one slit edge overlaps to other slit edge.

3. Structure as claimed in claim 1, wherein said fixing means consist of thin rings. 

1. In a roof bolt emplaced in a bore-hole, comprising a sleeveshaped member disposed in the bore-hole and having a plurality of apertures therethrough, a bolt extending lengthwise the interior of said sleeve-shaped member, and a quantity of cement mortar surrounding the bolt and extending through said apertures and filling the space between said sleeve-shaped member and the side walls of the bore-hole; the improvement in which the sleeveshaped member consists of a relatively rigid by resilient material, the circumferential surface of said member being interrupted by a longitudinal and relatively wide slit which allows the introduction of the cement mortar into the interior of said member and which under the influence of a radial pressure on said member on both sides of the said slit allows a variation of the diameter of the member while maintaining a desired, substantially circular cross-section and an adaptation thereof to bore holes of different sizes, and fixing means surrounding the sleeve-shaped member and maintaining said member compressed to a smaller diameter than when said member is uncompressed.
 2. Structure as claimed in claim 1, wherein said member is compressible to such an extent that one slit edge overlaps to other slit edge.
 3. Structure as claimed in claim 1, wherein said fixing means consist of thin rings. 